Electrical control in circular knitting machines



P 5, 5 R. SCHMIDT 3,339,381

ELECTRICAL CONTROL IN CIRCULAR KNITTING MACHINES Filed May 26, 1964 United States Patent 3,339,381 ELECTRICAL CONTROL IN CIRCULAR KNITTING MACHINES Richard Schmidt, Stuttgart-Vaihingen, Germany, assignor to Franz Morat G.m.b.H., Stuttgart-Vaihingen, Germany Filed May 26, 1964, Ser. No. 370,220 Claims priority, application Germany, Aug. 22, 1963, M 57,925 4 Claims. (Cl. 66-50) This invention concerns circular knitting machines which include electrically and/ or electronically controllable devices particularly for determining patterns to be produced by operating a plurality of knitting needles selectively during the rotary movement of a needle wheel carrying such needles. The invention is similarly applicable to similar machines in which command devices produce low voltage or low current pulses which are then amplified and applied to electrically operable or controllable devices, as a rule consisting of electromagnets.

It has been found that it is of very great importance to see to it that the impulses which energize the electrically operable devices of the knitting machine are of utmost uniformity. Even small fluctuations of the impulses can lead to a faulty timing of the commands to be transmitted to the operating devices. This will be understood if one bears in mind that for instance in a standard circular knitting machine up to 500 needles per second travel past the control point and a change of the needle position may be required for adjacent needles which arrive consecutively at the operating point.

In view of the above it is one object of this invention to provide in a circular knitting machine for an arrangement which is instrumental for maintaining a great uniformity of the control pulses which operate the electrically operable control devices of the machine.

It is a further object of this invention to provide for an arrangement as set forth which is comparatively simple and highly efficient in operation.

It will be seen that in the arrangement according to the invention an amplifier which serves to amplify the control impulses is supplied with direct current voltage produced by a direct current generator that is, in turn, driven by a three-phase motor receiving its energy from a threephase voltage supply network. In this manner already a great amount of uniformity of the direct current voltage applied to the amplifier is obtained. Moreover, according to the invention, the effect of voltage fluctuations in the supply network are eliminated by connecting a flywheel with the generator or with the motor, preferably on a drive shaft connecting the motor with the generator. The size of the flywheel may be selected in accordance with known rules in proportion to the rotary speed of the motor-generator assembly and to the power transmitted by the motor to the generator.

In this manner according to the invention the uniformity of the electrical impulses controlling the operation of the electrically operable elements of the knitting machine is brought to an extremely high level of uniformity.-

In view of the above the invention includes in a circular knitting machine including needle-carrying part-s rotating at a constant rotary speed and electronically controllable devices for determining patterns to be produced by operating a plurality of knitting needles selectively, in combination, electrically operable control means for selectively controlling the operation of individual needles out of said plurality thereof; record carrier means carrying a record of commands corresponding to a pattern to be produced; means for sequentially deriving from said record carrier means said commands in the form of low energy electric current pulses; amplifier means for amplifying said pulses and for furnishing the same to said control means for energizing the latter in accordance with said commands; direct current voltage generator means for energizing said amplifier means; three-phase motor means connected to a three-phase voltage supply network and driving said generator means; and flywheel means operatively connected with said generator means for keeping said direct current voltage and thereby said current pulses at a uniform level in spite of an occurrence of fluctuations in said three-phase voltage supply.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing, in which an arrangement according to the invention is illustrated diagrammatically, partly as a circuit diagram.

The illustrated example refers to a circular knitting machine including a pattern wheel.

Referring now to the drawing, it can be seen that a three-phase motor 2 connected with a three-phase supply network 1 is coupled by means of a shaft 3 with a direct current voltage generator 4 for driving the latter. A flywheel 3a is mounted on the connecting shaft 3. Cables 5a and 5b connect the output terminals of the generator 4 with an amplifier 6.

A record carrier 8 is provided and moved in synchronism with the needle cylinder 15 and the dial 17 in a well known manner and by means not shown in the direction of the arrow over guide rolls 9. Needle cylinder 15 and dial 17 are great masses so that the same and rolls 9 rotate at a constant uniform speed. The record carrier film is as usual provided with a pattern of transparent areas on a nontransparent background which corresponds to the pattern to be produced. A photoelectric arrangement is provided for deriving from the recorded pattern command corresponding control pulses for the electrically controllable devices of the machine. For instance, a source of light 7 is arranged on one side of the travelling film or record carrier 8 so that the light emanating from the source 7 is capable of pasing through the transparent pattern areas of the film 8, whenever they appear, and to impinge on a photo-sensitive element e.g. a photocell 10 which is con nected by lines 11a and 11b with the above mentioned amplifier 6. In this manner control impulses are applied by the photoelectric arrangement to the amplifier 6 where they are amplified and applied via lines 1311 and 13b for instance to the electromagnet 12 which cooperates with the pattern wheel 14 in such a manner that the conventional jacks of this pattern wheel 14 are moved into a predetermined position everytime an impulse is applied to the electromagnet 12. Of course it is to be understood that the electromagnet '12 may also be located on the pattern wheel 14 itself. It is well known that in accordance with the movement of the jacks of the pattern wheel during the rotation of the needle cylinder 15 the respectively associated cylinder needle 16 is moved into a desired effective position. Due to the fact that flywheel 3a maintains a constant rotary speed of generator 4, the energizing current applied to electromagnet 12 is constant and the same for each impulse, irrespective of voltage fluctuations of the three phase supply network, so that electromagnet 12 operates in synchronism with needle cylinder 15 and dial 17 which rotate at a constant speed. It may be noted that electrically operable knitting machines of this general type are known for instance from Uni-ted States Patents 3,076,- 325 and 3,079,775.

It is to be understood that for obvious reasons the current or voltage pulses furnished by the amplifier 6 may also be used for operating other electrically controllable devices eg pattern wheels which influence the dial needles 18 or devices which influence elements of the cylinder needle and/or dial needle cams, or the cylinder needles and/or the dial needles directly, or finally the movement of thread guides between two desired positions e.g. to and from operative position.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of a circular knitting machine differing from the types described above.

While the invention has been illustrated and described as embodied in a circular knitting machine including electronically controllable devices for determining patterns to be produced, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a circular knitting machine including rotary parts supporting knitting needles and rotating at a constant speed, and electronically controllable devices for determining pat-terns to be produced by operating a plurality of said knitting needles selectively, in combination, electrically operable control means for selectively controlling the operation of individual needles out of said plurality thereof; record carrier means carrying a record of commands corresponding to a pattern to be produced; means that the same operate in exact synchronism with said rotary parts and said needles if energized by a constant voltage; direct current voltage generator means for energizing said amplifier means; three-phase motor means connected to a three-phase voltage supply network and driving said generator means; and flywheel means operatively connected with said geneartor means for keeping said direct current voltage, which controls said control means, at a uniform level in spite of an occurrence of fluctuations in said three-phase voltage supply so that the current of said amplified pulses is constant and said control means are operated in synchronism with the constant rotary speed of said parts and said knitting needles.

2. In a circular knitting machine including rotary parts supporting knitting needles and rotating at a constant speed, and electronically controllable devices for determining patterns to be produced by operating a plurality of said knitting needles selectively during the rotary movement of a needle cylinder carrying said needles, in combination, electrically operable control means for selectively controlling the operation of individual needles out of said plurality thereof; record carrier means moving synchronously with the movement of the needle cylinder and carrying a record of commands in the form of a pattern of area portions of different transparency corresponding to a pattern to be produced; photoelectric means for sequentially deriving from said pattern of areas of diflerent transparency on said record carrier means said commands in the form of low energy electric pulses; amplifier means for amplifying said pulses and for furnishing the amplified pulses to said control means for energizing the latter in accordance with said commands so that the same operate in exact synchronism with said rotary parts and said needles if energized by a constant voltage; direct current voltage generator means for energizing said amplifier means; three-phase motor means connected to a three-phase voltage supply network and driving said generator means; and flywheel means operatively connected with said generator means for keeping said direct current voltage, which controls said control means, at a uniform level in spite of an occurrence of fluctuations in said three-phase voltage supply so that the current of said amplified pulses is constant and said control means are operated in synchronism with the constant rotary speed of said parts and said knitting needles.

3. In a circular knitting machine including a needle cylinder carrying knitting needles and rotating at a constant speed due to its mass, and devices for determining patterns to be produced by operating said knitting needles selectively, in combination, electromagnetic control means for said devices; record carrier means carrying a record of commands corresponding to a pattern to be produced; means for moving said record carrier means in synchronism with said needle cylinder; sensing means for sequentially deriving from said moving record carrier means selection commands in the form of electric pulses; amplifier means for amplifying said pulses and connected with said electromagnetic control means so that the same are energized by the current of said amplified pulses in accordance with said commands and operate in exact synchronism with the displacement of said needles by said needle cylinder if energized by a constant voltage; a voltage supply network; motor means connected with said network and being energized by the same; generator means having a shaft connected with said motor means for rotation so that said motor means drives said generator means, said generator means being connected with said amplifier means for energizing the same; and flywheel means secured to said shaft and rotating with said generator means for holding the voltage produced by the same and controlling said electromagnetic control means at a uniform level irrespective of fluctuations in said voltage supply network so that the current of said amplified pulses is constant and said electromagnetic control means are operated in exact synchronism with the constant rotary speed of said needle cylinder and said knitting needles.

4. A circular knitting machine according to claim 3 wherein said voltage supply network delivers a three-phase voltage; wherein said motor means is a three-phase motor means energized by said three-phase voltage; and wherein said generator means is a direct current voltage generator means for supplying a direct current voltage to said amplifier means.

References Cited UNITED STATES PATENTS 2,419,462 4/1947 Petch et al. 3224 X 2,480,635 8/1949 Dawson 3224 X 2,922,896 1/1960 Ohlund 3224 X 3,079,775 3/1963 Schaedar et al 6650 3,170,312 2/1965 Stack 665O 3,178,632 4/1965 Woodson et a1 3224 X 3,185,873 5/1965 Rosenfeld 3224 X 3,196,341 7/1965 Geib 3224 X MERVIN STEIN, Primary Examiner.

R. FELDBAUM, Assistant Examiner. 

1. IN A CIRCULAR KNITTING MACHINE INCLUDING ROTARY PARTS SUPPORTING KNITTING NEEDLES AND ROTATING AT A CONSTANT SPEED, AND ELECTRONICALLY CONTROLLABLE DEVICES FOR DETERMINING PATTERNS TO BE PRODUCED BY OPERATING A PLURALITY OF SAID KNITTING NEEDLES SELECTIVELY, IN COMBINATION, ELECTRICALLY OPERABLE CONTROL MEANS FOR SELECTIVELY CONTROLLING THE OPERATION OF INDIVIDUAL NEEDLES OUT OF SAID PLURALITY THEREOF; RECORD CARRIER MEANS CARRYING A RECORD OF COMMANDS CORRESPONDING TO A PATTERN TO BE PRODUCED; MEANS FOR SEQUENTIALLY DERIVING FROM SAID RECORD CARRIER MEANS SAID COMMANDS IN THE FORM OF LOW ENERGY ELECTRIC PULSES; AMPLIFIER MEANS FOR AMPLIFYING SAID PULSES AND FOR FURNISHING THE AMPLIFIED PULSES TO SAID CONTROL MEANS FOR ENERGIZING THE LATTER IN ACCORDANCE WITH SAID COMMANDS SO THAT THE SAME OPERATE IN EXACT SYNCHRONISM WITH SAID ROTARY PARTS AND SAID NEEDLES OF ENERGIZED BY A CONSTANT VOLTAGE; DIRECT CURRENT VOLTAGE GENERATOR MEANS FOR ENERGIZING SAID AMPLIFIER MEANS; THREE-PHASE MOTOR MEANS CONNECTED TO A THREE-PHASE VOLTAGE SUPPLY NETWORK AND DRIVING SAID GENERATOR MEANS; AND FLYWHEEL MEANS OPERATIVELY CONNECTED WITH SAID GENERATOR MEANS FOR KEEPING SAID DIRECT CURRENT VOLTAGE, WHICH CONTROLS SAID CONTROL MEANS, AT A UNIFORM LEVEL IN SPITE OF AN OCCURENCE OF FLUCTUATIONS IN SAID THREE-PHASE VOLTAGE SUPPLY SO THAT THE CURRENT OF SAID AMPLIFIED PULSES IS CONSTANT AND SAID CONTROL MEANS ARE OPERATED IN SYNCHRONISM WITH THE CONSTANT ROTARY SPEED OF SAID PARTS AND KNITTING NEEDLES. 